Which Types of Hydraulic Fluids Are Used in Aircraft?

Which Types of Hydraulic Fluids Are Used in Aircraft?

Sep 5th 2023

The aviation industry relies on various chemicals and additives to ensure aircraft reach their destinations safely and on time. Most planes rely on hydraulics for moving flaps, braking, and retracting the landing gear. Which types of hydraulic fluids are used in aircraft?

Mineral Base Fluid

Mineral-based oils are the most common fluids in aircraft hydraulics. They are derived from crude oil and go through an industrial process to remove impurities and make them suitable for operating complex machinery.

The use of mineral-based hydraulic fluids goes back decades, making them reliable solutions for systems where operators are concerned about fire hazards. They’re relatively cheap to produce and work well in small aircraft.

Phosphate Ester Base Fluid

Another common type of hydraulic fluid is manufactured with a phosphate ester base, improving its fire-resistant properties, and reducing the amount of vapor produced during operation. Phosphate esters have excellent heat stability and low volatility, which reduces wear on the engine and helps to extend its life.

Due to their properties, phosphate esters are common additives in anti-stripping agents and lubricants. They’re also excellent for aircraft hydraulics because they offer operators precise control over the system.

Synthetic Hydrocarbon Base Fluid

Rather than using petroleum, some manufacturers opt for a synthetic chemical base to produce hydraulic fluid. Synthetic fluids have unique properties that don’t exist in natural chemicals.

Synthetic hydraulic fluids reduce friction in the hydraulic system, reducing the heat generated and improving efficiency. The molecular structure of hydrocarbons makes it possible to reduce viscosity and leaks. In addition, hydraulic grease is great for sealing or lubricating the system, improving its performance.

Hydraulics Make Air Travel Possible

Modern air travel wouldn’t be very convenient without hydraulics. Whether for safety or controlling the flight mechanisms, fluids are essential for getting aircraft off the ground. Knowing which types of hydraulic fluids are used in aircraft can give you some insight into the importance of this technology for our fast-paced lives.